Optimization of media for in vitro plant cultivation by the example of water sorrel ( Rumex aquaticus L.)

Accumulation of polyphenols makes a real problem under in vitro plant propagation because of toxic effects of phenol oxidation products to callus tissue, and in some cases a frequent subculturing is required. We screened the possible media components for decreasing negative effects of polyphenols to cell proliferation and viability under cultivation, callus tissue of Sorrel aqueous Rumex aquatics L. used as a model. Callus was induced from leaf explants on basal Murashige and Skoog medium with benzyladenin-6 and a-naphthylacetic acid. Derived callus was subcultivated on the same medium with the addition of sorbents (polyvinylpyrrolidone) and antioxidants (sodium thiosulfate). There is the prolongation of life of callus without frequent subculturing by reducing accumulation of polyphenols in the tissues. Through quantitative studies of the amount of polyphenols by a modified method of Folin-Chokalteu, it was established that the concentration of phenolic compounds in the tissues in the classical media with long-term cultivation made up to 7 mg per 1 g of callus tissue, if re-counted to gallic acid, followed by a growth arrest and cell death. In contrast, in the modified media a content of polyphenols is an average of up to 2 times lower than in the callus tissue grown in the medium without use of adsorbents and antioxidants.